1. Field of the Invention
The present invention relates to a Hall IC type current sensor of a vehicle-mounted power converter, particularly to the fixing structure of a Hall IC for detecting a current value of a bus bar for a large current and the connection structure of the Hall IC to a control board on which a control circuit for controlling a vehicle-mounted power converter is formed.
2. Description of the Related Art
A conventional current sensor for a large current which is used for a vehicle-mounted power converter is configured as follows. That is, a Hall IC having a printed circuit board on which a known Hall element, an electric circuit which amplifies an output signal of the Hall element and a constant current circuit are formed is fixed to a bus bar formed of a conductive member for supplying electricity to the vehicle-mounted power converter. Further, a lead terminal which supplies a power source to the Hall IC and a lead terminal which takes out an output signal from the Hall IC are connected with a control board on which a control circuit for controlling vehicle-mounted power converter is formed via connectors (see Japanese Unexamined Patent Publication 2003-299364 (paragraph 0020, FIG. 1).
In the device having such a constitution, the vehicle-mounted power converter is, for example, constituted of a semiconductor switching element, wherein the semiconductor switching element receives a DC power or an AC power from an external power source via a bus bar, and after power conversion, the electric power is supplied to a suitable electric load. Here, a magnetic flux is generated in a bus bar in the direction perpendicular to a flowing current and hence, a Hall element is mounted in the direction perpendicular to the magnetic flux on a magnetic circuit so as to convert the power into an electric signal corresponding to the density of magnetic flux, the electric signal is amplified by an electric circuit in the inside of the Hall IC and, at the same time, the electric current is transmitted to a control board via a lead terminal and a connector thus controlling the vehicle-mounted power converter in response to a current value of the bus bar.
The conventional current sensor for a large current has the above-mentioned constitution and the connection of the lead terminal of the Hall element and the control board is performed using the connector and hence, when such a current sensor is provided for a vehicle use which receives strong vibration, there has been a drawback that the current sensor lacks reliability in connectivity. Further, the current sensor for a large current is often large-sized and costly and hence, the current sensor is constituted of parts which largely obstruct the miniaturization and the reduction of cost which are requisite for the vehicle-use device which must be mounted in a limited space.